Counter



w; FISCHER April 14, 1970 COUNTER Filed March 21, 1968 r 5 E #%M H, D 4 MM fi F w United States Patent O M US. Cl. 23582 Claims ABSTRACT OF THE DISCLOSURE The invention provides a step-by-step counter having a figure roll and a detent for locking each counting step of said figure roll. At least one key is provided for operating the figure roll. The length of travel of said key being shorter than each individual counting step to be elfected by the figure roll, said detent is designed and arranged automatically to complete each individual counting step of the figure roll.

BACKGROUND OF THE INVENTION This invention relates to a step-by-step counter having a detent for locking each counting step.

Counters of this type are already known in the art. In these counters, the detent generally becomes effective upon completion of each stepping operation and has sometimes additionally a centering function. Such arrangements have already been used for counters capable of being stepped in two directions. For example, in a known counter which can be stepped forward and backward a tommy bar is provided which by being forced down or up will operate the figure roll to effect an adding or a subtracting cycle, respectively. A different form of construction uses a tumbler switch, the actuating pieces of which are located above and below a window in which the respectively indexed figure becomes visible. This arrangement, too, provides an adding and a subtracting direction of operation. Such counters are used, for example, in the field of control engineering where measuring, control and indicating devices as well as preselector switches are required. A disadvantage in these known counters is particularly the fact that for operation in the subtracting and adding directions a single switch is provided the direction of operation of which is easy to confound.

In a further known counter the figure roll itself can be stepped in both directions of rotation. For this purpose the roll is provided on its circumference with teeth which carry the figures on their upper side and serve as switching handles during the stepping operation. In the inoperative position, a detent engages between these teeth. In this form of construction it is particularly disadvantageous that in order to enable the stepping operation to be effected, the casing must have an opening for the toothing so that it is possible for dust and impurities to enter the interior of the casing. Moreover, the manufacture of such a toothed figure roll is rather expensive. In addition there is the danger that after prolonged use the figures will be blurred by handling the teeth and become illegible.

A substantial disadvantage of all these prior art designs consists in that the required stepping travel is relatively large.

SUMMARY OF THE INVENTION It is the object of the present invention to provide a counter in which such disadvantages are eliminated.

To attain this object, the present invention provides a counter of the initially described type which comprises a casing; a roll provided with consecutive figures and rotatably mounted in said casing; at least one key for rotating 3,506,190 Patented Apr. 14, 1970 said roll from one figure towards a neighbouring figure, the length of travel of said key being shorter than the distance between the consecutive figures would require, and a detent fixed at one end to said casing and having its free other end constructed so as automatically to complete each stepping operation.

Using the detent for completing each stepping operation has, in particular, the advantage that the travel of the key can be reduced so that the counter can be realized in a compact construction.

For stepping the figure roll in both directions of rotation two oppositely acting keys may be provided, one key for operating adding cycles and the other key for operating subtracting cycles of the counter.

The oppositely acting keys may be disposed one above the other so that upon operation of the keys these will engage indexing pins on different sides of the figure roll center. In this arrangement the keys when being operated may engage by means of a respective dog the indexing pins disposed in a circle, whereas the indexing pins are disengaged from the dogs when the keys are in their inoperative position.

The upper key may be provided for operating adding cycles and the lower key may be provided for operating subtracting cycles of the figure roll, thereby to ensure easy and simple operation of the counter.

It is advantageous if the key and its associated dog consist of one piece, preferably of plastics. Moreover, every key can be provided with a restoring spring, which preferably is formed as a pressure spring.

The detent may be designed for engagement into the space between two adjacent indexing pins, thereby giving the indexing pins a dual function.

The detent suitably comprises a detent spring having a wedge-shaped end adapted to be urged by resilience into the space between two adjacent indexing pins.

The figure roll including its bearings and moving parts is expediently accommodated in a closed casing provided with a window to enable the respectively indexed figure to be read, and the window is provided with a cover of transparent material which is preferably vaulted like a magnifier. Thereby dust and impurities are prevented from penetrating the casing. Such magnifier type vaulting of the window results in a better and more distinct showing of the figures. At one of its ends the figure roll may be connected to a switching plate through the intermediary of resilient wipers. In this manner it will be obtained that, on the one hand, the contact corresponding to the stepped position of the figure roll is closed and, on the other hand, the figure roll is locked in the desired position.

BRIEF DESCRIPTION OF THE DRAWING An embodiment of the invention will now be described by way of example and with reference to the accompanying drawing, in which:

FIG. 1 is a sectional view of a counter incorporating the invention, one wall of the casing having been omitted;

FIG. 2 is a cross section through the counter, taken on line II-II of FIG. 1;

FIG. 3 is a front view of the counter, partly in section, taken on line lII-III of FIG. 1, and

FIG. 4 is a view similar to FIG. 1,,one key having just completed its travel.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIGS. 1 to 4 show a step-by-step counter 1 accommodated in a closed casing G and provided with a detent 2 for locking each step. The counter 1 comprises a figure roll 3 provided with figures 4 from zero to nine. FIG. 3 shows part of the the figures 4 and the manner in which they are arranged. The figure roll 3 is formed of a cylinder having a smooth circumferential surface in which the figures 4 are engraved, for example. It is self-evident that the figures 4 may also be printed on the smooth circumferential surface of the cylinder. This enables a dust-proof accommodation in the closed casing G to be realized. Moreover, the manufacture of such a cylinder is simple.

For stepping the counter 1 so as to obtain both adding and subtracting cycles two keys 50 and 5a are provided and arranged for counteracting operation. In the illustrated embodiment the keys 50 and Su are disposed one above the other and formed integral with dogs 6 for engagement, upon operation of the keys, with equidistantly spaced indexing pins 7 disposed in a circle on one of the end faces S of the figure roll 3. The dogs 6 of the keys 50 and Su will in each case engage indexing pins 7 on different sides of the figure roll center indicated by the reference numeral 8. By operating, for example, the upper key 50, as shown in FIG. 4, the figure roll 3 will be stepped in clockwise direction. With the chosen sequence of the figures 4 this will result in an adding cycle of the counter 1. Accordingly, by operating the lower key Su a subtracting cycle of the counter 1 will be obtained. To improve the usability of the device, the design of the two keys 50 and 5a may differ from each other, preferably in color or, if desired, in shape, according to their different functions. For example, the subtraction key Su may be colored red, thereby to reduce the risk of unintentional operation of the key Su.

The number of the indexing pins 7 equals that of the figures 4. As shown particularly in FIG. 4 each key has an associated restoring spring 9 which in the illustrated embodiment is provided in the form of a compression spring.

For supporting and guiding the keys 50 and Su guide pins 11 engaging in respective slots 12 in the keys are mounted in the front wall of the casing G. The slots 12 also accommodate the restoring springs 9 which are thus supported between the movable keys and the stationary guide pins 11. To save space, the two keys 50 and Su are each provided with a recessed portion 13 on their sides facing each other, which recessed portions 13 are in sliding contact with a mounting bolt 14 for the figure roll 3. For relieving the guide pins 11 each key is provided with a projection 15 for limiting the return of the keys to their inoperative positions and, above all, for scaling in these positions the key passage in the casing G.

As shown in FIGS. 1 and 4, the detent 2 comprises a detent spring 16 having a wedge-shaped end 17 urged by resilience into the space between two adjacent indexing pins 7. According to an essential feature of the invention, consequently, the length of travel of each key is shorter than the individual counting step to be effected by the figure roll 3. In addition to its centering and locking function the detent spring 16 also serves automatically to complete a stepping operation. In the illustrated embodiment, the part of the counting step corresponding to the length of travel of the keys is slightly greater than one half of a full counting step to be completed by the detent spring 16. In FIG. 4, by the travel of the upper key 50 the figure roll 3 has been rotated into a position in which an indexing pin 7a has just passed below the apex 18 of the wedgeshaped end 17 of the detent spring 16. To reach this position a certain resistance of the detent 2 has to be overcome in a known manner. When the key 50 is released, it will be returned into its inoperative position by the associated restoring spring 9, and the apex 1-8 of the wedgeshaped end 17 will be urged into the space between the two indexing pins 7a and 7b by the locking force of the detent spring 16, as shown in FIG. 1. To achieve this end it is necessary that the indexing pins 7 in the inoperative position are released by the dogs 6 on the keys so that the completion of a counting step by the detent spring 16- is not obstructed. Giving the wedge-shaped end 17 of the detent spring 16 a substantially symmetrical configuration enables the described counting step in both directions to be initiated by means of the corresponding key 50 or 5a, and to be completed by the detent 2. In this manner it is possible to keep the required length of travel of the keys 5 relatively short.

The respectively indexed figure 4 will become visible in a window 19 in a side wall 20 of the casing G. In the illustrated embodiment, the window 19 is protected against the penetration of dust or impurities by a magnifying glass type arched cover 19a which also provides for an improved reading of the respectively indexed figure 4. To save weight and material the figure roll 3 is provided with an annular recess 21. One end face of the figure roll 3 is connected to a detachable switching plate 23 by means of resilient wipers 22 which ensure that, on the one hand, an electric contact 24 corresponding to the respectively indexed figure 4 is closed and that, on the other hand, the figure roll 3 is secured against axial displacement.

An advantage of the present invention consists in that operating errors of the counter 1 are largely prevented by the appropriate arrangement of the keys 50 and 5a. By using the detent 2 for completing the individual counting steps a reduced length of travel of the keys is obtained which results not only in a simplified and more expeditious operation but also in a more compact design of the counter 1, which is desired when using the counter 1 as a structural part.

A further considerable advantage is the dust-proof accommodation of the counter, which results in increased service life and improved function.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof.

What is claimed is:

1. A step-by-step counter comprising a casing including a front Wall, a rear wall and a side wall, a shaft mounted for rotation between said walls, a figure roll fixedly secured to said shaft, said figure roll having its circumferential surface impressed with figures from zero to nine, said figure roll having one end provided with circularly arranged equidistantly spaced indexing pins extending laterally of said one end, the number of said pins equaling the number of said figures, key means in said casing for rotating any one of said indexing pins in a predetermined direction short of the distance required to complete a stepping operation, spring detent means cooperating with adjacent indexing pins for preventing inadvertent rotation of said figure roll and for completing a stepping operation when one of said indexing pins is moved past said spring means by said key means and electrical contact means on the other end of said figure roll, corresponding to said indexing pins.

2. The device according to claim 1, wherein said key means comprises at least one key formed with a longitudinal slot, a guide pin in said front wall extending through said longitudinal slot for guiding said key, said key further formed with an integral dog engageable with said indexing pins for rotating said figure roll part way of stepping operation and a restoring compression spring in said longitudinal slot, normally biasing said key away from said indexing pins.

3. The device according to claim 2, wherein said key is provided with a projection for limiting the return of said key to its inoperative position.

4. The device according to claim 1, wherein said spring detent means comprises a flat spring having one end secured to said front wall, the other end of said spring being formed as a wedge disposed in the path of travel of said indexing pins, said wedge furthering the travel of an indexing pin to complete a stepping operation, when an indexing pin is moved by said key means past said wedge.

5. The device according to the claim 1, wherein said side wall is formed with an opening and a magnifying 5 6 cover of transparent material in said opening for enabling 3,022,942 2/1962 Van Veen 235-82 the reading of said figures on said figure roll. 3,343,789 9/1962 Wales et a1 235-132 References Cited RICHARD B. WILKINSON, Primary Examiner UNITED STATES PATENTS 5 S. A. WAL, Assistant Examiner 1,657,828 1/ 1928 Henderson 235-117 2,904,251 9/1959 Hazard et a1. 235-132 3,006,546 10/1961 La Pointe 23s 117 X 117 

